Various techniques, such as side-channel attacks, have been developed for extracting information from electronic devices. The attacks are typically performed by unauthorized parties in order to access secret information stored within the devices. Side-channel attacks take advantage of the fact that electronic devices typically consume power during transitions of logic elements. The attacks extract information by non-invasively measuring electrical signals and/or radiation emitted from the devices, without electrically contacting the devices that carry the information.
A number of attempts have been made to develop techniques that can be implemented in electronic devices to protect secret data from unauthorized discovery by means of side-channel attacks. Some techniques of this sort are described in references cited in PCT International Publication WO 2013/035006, to Shen-Orr, et al., whose disclosure is incorporated herein by reference. The disclosure describes a method for data transfer, which comprises receiving a control signal triggering a transfer of a secret value into an element of a circuit. In response to the control signal, a dummy value and the secret value are inserted in succession into the element of the circuit.
Documents incorporated by reference in the present patent application are to be considered an integral part of the application except that to the extent any terms are defined in these incorporated documents in a manner that conflicts with the definitions made explicitly or implicitly in the present specification, only the definitions in the present specification should be considered.